In situ monitoring of dynamic H2O2 produced upon the external stress of plants using Ag@ZIF-67 based fluorescence sensor

Sensitive and dynamic detection of H2O2 is of great importance because it is regarded as an acute stress indicator in plants that mediates rapid system transduction. Herein, we constructed a sensitive fluorescence (FL) sensor for in situ monitoring of dynamic H2O2 produced upon the external stress of plants using silver nanoparticles modified zeolitic imidazolate frameworks (Ag@ZIF-67). In the sensor, Pacific Blue functionalized probe DNA (Pacific Blue-probe DNA) were firstly immobilized onto the surface of Ag@ZIF-67 via Ag-S bonds, making the sensor in a "signal-off" state due to the quenching of Ag NPs to Pacific Blue. In the presence of H2O2, Ag NPs could be resolved into Ag+, accompanied with the release of Pacific Blue-probe DNA and the recovery of FL intensity. Relying on the FL signal, the sensor could in situ report the dynamic H2O2 concentration on the plant root, petiole or leaf upon the external stress such as mechanical damage, pathogens, or high temperature. Such in situ sensing platform possess potential application prospect in detecting other signal pathways of active plants.